Ev charging system

Abstract

A circuit and methods including super-twisting sliding mode controller (ST-SMC) control of an AC/DC quasi single-stage current-fed resonant converter for electric vehicle (EV) charging. The converter includes primary side switches and a secondary side bidirectional switch, achieving zero-voltage switching (ZVS) for efficient operation. The primary side includes an active clamp circuit, while the secondary side incorporates a resonant tank for smooth energy transfer. The ST-SMC generates pulse width modulation signals, ensuring ZVS at turn ON and turn OFF for primary switches, and ZVS at turn ON with low-voltage switching at turn OFF for the bidirectional switch. The circuit includes a feedback loop with an error calculation unit for precise control of grid current and output voltage, providing power factor correction and regulated output for 400V and 800V EV batteries.

1 . A charging system for an electric vehicle battery, comprising:
 a power grid,   a battery pack,   an AC/DC transformer-based converter including a plurality of primary side switches and a secondary side bidirectional switch; and   a super-twisting sliding mode controller operatively connected to the plurality of primary side switches and the secondary side bidirectional switch, wherein the super-twisting sliding mode controller is configured to generate pulse width modulation signals which switch a polarity of the plurality of primary side switches with zero-voltage switching error at turn ON and at turn OFF and switch the secondary side bidirectional switch with zero-voltage switching error at turn ON and with low-voltage switching error at turn OFF,   wherein the power grid, the battery pack, the AC/DC transformer-based converter and the super-twisting sliding mode controller are operatively connected.   
     
     
         2 . The charging system of  claim 1 , wherein a primary side of the AC/DC transformer-based converter comprises:
 an active clamp circuit including:
 a clamp capacitor; 
 a bridge rectifier connected to the clamp capacitor, wherein the bridge rectifier includes the plurality of primary side switches; 
 an alternating voltage source; 
 an inductor-based current doubler including a first inductor in parallel with a second inductor, wherein a first end of the first inductor and a first end of the second inductor are connected to a positive terminal of the alternating voltage source; and 
   a primary side coil connected to the bridge rectifier, wherein a positive terminal of the primary coil is connected to a second end of first inductor and a negative terminal of the primary side coil is connected to a second end of the second inductor.   
     
     
         3 . The charging system of  claim 2 , wherein each primary side switch includes:
 a metal oxide silicon field effect (MOSFET) transistor, an antiparallel diode and a switch capacitor in parallel with the MOSFET and the antiparallel diode, and   a drain terminal, a source terminal and a gate terminal.   
     
     
         4 . The charging system of  claim 3 , wherein the plurality of primary side switches of the bridge rectifier comprise:
 a first primary side switch connected at its drain terminal to the second end of the first inductor and connected at its source terminal to a negative terminal of the alternating voltage source;   a second primary side switch connected at its drain terminal to the second end of the second inductor and connected at its source terminal to a negative terminal of the alternating voltage source;   a third primary side switch connected at its drain terminal to a positive terminal of the clamp capacitor and connected at its source terminal to the second end of the first inductor; and   a fourth primary side switch connected at its drain terminal to the positive terminal of the clamp capacitor and connected at its source terminal to the second end of the second inductor,   wherein the positive terminal of the primary coil is connected to the bridge rectifier at the source terminal of the third primary side switch and the negative terminal of the primary coil is connected to the drain terminal of the second primary side switch.   
     
     
         5 . The charging system of  claim 4 , wherein the AC/DC transformer-based converter comprises:
 a secondary side coil;   a transformer operatively connected to the primary side coil and the secondary side coil; and   an active voltage doubler circuit.   
     
     
         6 . The charging system of  claim 5 , wherein the active voltage doubler circuit comprises:
 two diodes, a resonant inductor, and two resonant capacitors; and   a first secondary side switch and a second secondary side switch comprising the secondary side bidirectional switch,   wherein each secondary side switch includes a drain terminal, a source terminal and a gate terminal, wherein the source terminal of the second secondary side switch is connected to the source terminal of the first secondary side switch,   wherein each secondary side switch includes a metal oxide silicon field effect (MOSFET) transistor, an antiparallel diode and a switch capacitor in parallel with the MOSFET and the antiparallel diode.   
     
     
         7 . The charging system of  claim 6 , wherein the secondary side of the AC/DC transformer-based converter further comprises:
 a secondary coil; and   a first end of the resonant inductor connected to a positive terminal of the secondary coil, wherein:
 the drain terminal of the first secondary side switch is connected to a second end of the resonant inductor, 
 the drain terminal of the second secondary side switch is connected to a negative terminal of the secondary coil. 
   
     
     
         8 . The charging system of  claim 7 , wherein the secondary side of the AC/DC transformer-based converter further comprises:
 a first diode of the two diodes having an anode connected to the second end of the resonant inductor and to the drain terminal of the first secondary side switch of the bidirectional switch; and   a second diode of the two diodes having a cathode connected to the second end of the resonant inductor and to the drain terminal of the first secondary side switch of the bidirectional switch.   
     
     
         9 . The charging system of  claim 8 , wherein the secondary side of the AC/DC transformer-based converter further comprises:
 a first resonant capacitor of the two resonant capacitors having a positive terminal connected to a cathode of the first diode and a negative terminal connected to the negative terminal of the secondary side coil; and   a second resonant capacitor of the two resonant capacitors having a positive terminal connected to the negative terminal of the secondary side coil and to a negative terminal of the first resonant capacitor, wherein the second resonant capacitor has a negative terminal connected to an anode of the second diode.   
     
     
         10 . The charging system of  claim 9 , wherein the secondary side of the AC/DC transformer-based converter further comprises:
 an output capacitor having a first terminal connected to the positive terminal of the first resonant capacitor and a second terminal connected to the negative terminal of the second resonant capacitor,   wherein a voltage across the output capacitor and a current generated by the bidirectional switch are configured to charge a battery of the battery pack, wherein the battery pack is in the electric vehicle.   
     
     
         11 . The charging system of  claim 10 , wherein:
 the super-twisting sliding mode controller is configured to transmit the pulse width modulation signals to the gate terminals of the plurality of primary side switches of the bridge rectifier, to the gate terminal of the first secondary side switch and to the gate terminal of the second secondary side switch of the secondary side bidirectional switch; and   the pulse width modulation signals are configured to operate the AC/DC transformer-based converter in a first mode, a second mode, a third mode and a fourth mode, wherein:
 the pulse width modulation signals of the first mode are configured to turn ON the second secondary side switch and then turn ON the first primary side switch, the fourth primary side switch and the first secondary side switch with zero voltage switching error, transfer a voltage stored on the clamp capacitor through the primary coil to the secondary coil, charge the switch capacitors of the first primary side switch, the fourth primary side switch, the first secondary side switch and the second primary side switch, and charge the battery of the electric vehicle with the voltage; 
 the pulse width modulation signals of the second mode are configured to turn OFF the second secondary side switch with low voltage switching error and charge the first resonant capacitor, the second resonant capacitor and the output capacitor, and charge the battery of the electric vehicle with the voltage on the output capacitor; 
 the pulse width modulation signals of the third mode are configured to charge the switch capacitor of the second secondary side switch and discharge the output voltage to the battery of the electric vehicle; and 
 the pulse width modulation signals of the fourth mode are configured turn OFF the first primary side switch and the fourth primary side switch with zero voltage switching error, turn ON the second primary side switch and the third primary side switch with zero voltage switching error, and continue to discharge the output voltage to the battery of the electric vehicle. 
   
     
     
         12 . The charging system of  claim 11 , further comprising:
 a feedback loop connected between the alternating voltage source and the output voltage of the AC/DC transformer-based converter and the super-twisting sliding mode controller; and   an error calculation unit located in the feedback loop, wherein the error calculation unit is configured to receive a grid current of the alternating voltage source and a grid reference current generated by the super-twisting sliding mode controller, the output voltage and a reference voltage and calculate a current error signal and a voltage error signal and transmit the current error signal and a voltage error signal through the feedback loop to the super-twisting sliding mode controller, wherein the super-twisting sliding mode controller is configured to generate the pulse width modulation signals based on the current error signal and the voltage error signal.   
     
     
         13 . The charging system of  claim 12 , further comprising:
 the super-twisting sliding mode controller includes electrical circuitry, a memory storing program instructions and at least one processor configured to execute the program instructions, wherein the program instructions include a sliding mode surface algorithm and a super twisting algorithm, wherein the at least one processor is configured to execute the sliding mode surface algorithm and a super twisting algorithm to generate the pulse width modulation signals.   
     
     
         14 - 20 . (canceled)